Protection device for tumbler locks



Nav. 13, 192s. 1,691,030 E. M. BENHAM ET AL PROTECTION DEVICE FOR TUMBLER LOOKS Fued Jan. 1o, 1927 2 sheets-sheet 2 INVENTO ZW 1 /@L mi? 17 ATTORNEY standard constructions.

Patented Nov. 13, 1928.

. f UNITED STATES PATENT oFFicE.

EDGAR M. BENHAM AND WILLIAM T. BENI-IAM, OF NORWOOD, OHIO, ASSIGNORS TO THE MOSLER LOCK COMPANY, OF COVINGTON, KENTUCKY, A CORPORATION OF OHIO.

PROTECTION DEVICE FOR TUMBLER LOCKS.

This invention relatesto locks and more particularly relates to a protection device for tumbler locks designed to frustrate attempts to open the lock by tampering with the mechanisml in an unauthorized manner.

Tumbler locks especially the combination locks for safes, and the like, which have a spindle for setting the combination tumblers, are frequently constructed in such a way that the lock can be opened readily after a persen has succeeded in removing the knob from the spindle and then driving the spindle inwardly into the safe. This is due to the fact that in these constructionsthe tumblers are carried on the rear cover plate of thelock which is torn away when the spindle isk driven inwardly.

The principal object of this invention is to provide means for preventing the lock from being unlocked afterr the spindle, tumblers and back plate have beenforced outof place, thus frustrating unlawful attempts to enter the protected structure 'by displacing vthese parts of the lock. A further object of this invention is to provide a protection device of the character referred to which does not interferein the least with thenormal operation of Y the lock, and effects no .change in the usual manner of manipulation. A further object of this invention is to provide a protection device of the character described which is etlicient, yet simple and inexpensive in construction, and one which is adapted to be associated Vreadily and easily with locks of different Other objects of this invention will be in part obvious and in part pointed out hereinafter. l f In accordance with this invention, the protection device comprises means, for instance, a catch or lug, which is adapted automatically to engage and hold the bolt bar in locked position as soon as and as 4long as a certain part of the lock, for instance, the rear cover plate, is displaced from its'normal position,

said means, however, being continually maintained in posit-ion out of engagement with the bolt bar so long as the controlling lock part isY in proper position. Y

In order that a clearer understanding of this invention may be had, attention is hereby directed to the accompanying drawings, forming a part of this application, and illustrating one possible embodiment of the in= vention.

Referring to the drawings, Fig. 1 is a sectional view, partly in elevation, of a mounted combination lock assembly, embodying this invention Fig. 2 is area-r view of thelock;V

Fig. 3 .is anl interior view thereof,.taken beneath the rear cover plate, rand on the line 3 3 of Fig. 1; Fig. 4 is a sectional view of the lock case and bolt bar with the rear cover plate displaced, and is taken o'ntlie line 4-4 of Fig. 3; and Fig. 5 is afview similar to Fig. 4 but shows the rear cover plate in place.` Similar reference characters refer to similar parts throughout the several views ofthe drawings. y Referring to the drawings,.the lock, in the main, is of standard construction, comprising a case 1, rear cover plate 2, provided with an arbor, 3 on which the combination tumblers 4 are mounted, and a drive tumblerV 5 mounted on the operating spindle 6 which projects through thewalltdouble) 7 of the protected structure, and which carries the usual dial 8 and operating knob 9. The lock case is secured to the wall 7 by means ofscrews 10. Mounted within the case are the slidable to engage in a notch 20 in the bolt b ar 12 when the springis allowed to assume its own n position. rlhis spring, however, is normallyheld with it-s end 18 `out vof the notch in bolt bar by means of a plunger 21 which is slidably seated in a guide recess 22 in the lock vcase..r At one end plunger 21engages the spring, rand at its other end is engaged by al pin 23 carried on the rear coveruplate of the lock. `'Iheguideway 22 mayconveniently be formed in oneof the bosses 23 which are en'- gaged by the screws 24 which secure the rear cover plate on thecase. i

So longas the cover plate 2 is in place the spring catch 18 is maintained out of engagement with the bolt bar, and the lock may be operated in the normal and usual manner. This is due to the plunger 21 being .held depressed by its engagement with coverpin 23, asflong as the cover is in place.

Asasoo'n yas the cover plate with .its kpin` 23 is displaced from the case, spring 14: moves inwardly of the lock case and its angular end 18 moves into the notch 20 `of the bolt bar and prevents the bolt bar from being retracted into unlocked position, even when the combina-4 f the bolt bar. lt is also apparent that locks of many standard constructions may be equipped reaoily and easily with the prot-ection device described above.

If desired, instead of providing the pin 23 on t-he cover plate the plunger 21 may beV lengthened so as to be engaged and depressed by direct Contact with the cover plate 2. It is expected that other possible modifications Within the scope of this invention Will be apparent to those skilled in the. art. Accordingly, as many changes could be made in the above construction and as many apparently widely different embodiments of this invention could be made Without departing from the scope thereof, it is understood that lall matter contained in the above description or shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense.

What We claim is 1. The combination with a lock including a bolt bar having a notch, of means, including a plate spring self-engageable in the notch of the bolt bar, for preventing` unlocking movement of the bolt bar, and means, including a. lock element, for maintaining said l plate spring disengaged from the notch of said Vbolt bar only while said element is in its proper place in the lock assembly.

2. In a lock of the character described, in combination, a case, a cover plate therefor, a bolt bar Within the case, said bolt bar having a notch therein, a plate spring secured to the case and having an end self-engageable in the notch of the bolt bar, a plunger in the case extending from the spring to vadjacent the cover plate, and means, including the cover plate, for depressing the plunger to hold the spring out of engage-ment with the notch of said bolt bar only while the cover plate is in proper position on the lock case.

3. In a lock of the character described, in combination, a case having a depression in the outer surface thereof, a bolt bar Within said case, said bolt bar having a notch therein, means self-engageable with said not-ch in said `bolt bar mounted kWithin said depression and extending through the case, for locking the bolt bar against movement, and means, including a lock element which maintains said iirst means out of engagement with said notchwhen said lock element is in normal position.

4f. In a lock of the character described, in

combination, a case having a depression in the outer surface thereof, said outer face being adjacent to the wall-of the protected structure forming therewith a chamber, a bolt bar Within said case, said bolt bar-having a notch therein, means mounted Within said depression, extending through an aperture in the case and self-engageable with said notch 'in said bolt bar, for locking the bolt bar against movement, and means, including a lock element which maintains said iirst means out of engagement with said notch when said lock element is in normal position.

5. `In a lock of the character described, in combination, a case, a Cover plate therefor, a bolt bar Within the case, a. spring plate on the case self-engageable with the bolt bar for preventing unlocking movement thereof, said case having a guide recess, and a plunger buried therein and adapted to hold said spring plate out of engagement with the bolt bar as long as the l,cover plate is in normal position on the case. Y

6. In a lock of the character described, in combination, a case, a-cover plate therefor, a bolt bar Within the case, a spring catch device secured to said ca'se exteriorly thereof, said catch device having a portion project'- ing into said case and engageable with said bolt bar for preventing unlocking movement thereof, and means associated With said cover plate for normally holding said spring catch out of engagement With said bolt bar.

This specificationsignedrthis 6th day of January, 1927. Y

EDGAR M. BENHAM. VILLIAM T. BENHAM. 

